3 Chapter 4 VocabActive transport-transport across the cell membrane that requires energyPassive transport-movement across the cell membrane that does not require energy.Concentration gradient-difference of concentration across a spaceOsmosisDiffusion6. Facilitated Diffusion7. Aquaporin8. Endocytosis9. Exocytosis10.receptor protein- a protein on the cell membrane that receives a signal molecule.11. Hypertonic12. Hypotonic13. Isotonic
4 Main Function of the Cell Membrane Membranes are selectively permeable so they control what moves in and out of the cellBased on size and polarity
8 So what moves in and out? Size Polarity In Out Small molecules Non-polar and some small polar moleculesOutLarge moleculesPolar
9 Passive Transport: Requires NO Energy Every cell exists in a liquid environment.Every cell must maintain homeostasisCells must regulate transport across the cell membrane
10 Concentration Gradients: the differences in concentration across a space.
11 Equilibrium B. equal concentrations across a space.
12 Diffusion: the movement from an area of high concentration to an area of low concentration. 1) a difference in concentration exists across the cell membrane2) diffusion occurs down the gradient.
13 Cell membrane is selectively permeable A. repels non polar molecules and ions.B. polar molecules and very small molecules can diffuse across the cell membrane.
14 Ion Channel: a polar pore through which ions can pass into a cell. A. some molecules cannot pass directly through the cell membrane.B. Ion channels- allows polar molecules, (like ions) pass into the cell.
15 Facilitated Diffusion: Sugars and amino acids A. carrier proteins -bind to substances outside the cell and carry it inside.B. Amino acids and SugarsC. Down the concentration gradient.D. NO ENERGY REQUIRED
16 Osmosis: the diffusion of water through a selectively permeable membrane. A. uses a concentration gradientB. passive transportC. Aquaporins-water channel proteinsD. This is a type of facilitated diffusion
22 How to Deal with osmotic pressure? A. contractile vacuole-a water pump found in parameciumB. cell walls- keeps central vacuole from over expanding.Large organisms cells are bathed in blood or isotonic solutions
23 Review Questions 1. What is a concentration gradient? 2. Describe the movement of molecules during diffusion.3. Can polar molecules pass through the cell membrane? Why or why not?What is a aquaporin?5. What is the difference between a hypotonic, hypertonic and an isotonic solution.6. What is passive transport?
24 Label the following cells as Isotonic, hypotonic, or hypertonic Image from
25 Active Transport: Requires ATP A Requires ATP1. Carrier proteins-act as pumps2. Against the concentration gradient.B. Sodium-Potassium Pump1. Sodium ions-more on outside of cell2. Potassium ions- more on inside of cell
26 How do you get Big Molecules across the cell membrane?
31 Exocytosis A. the movement out of the cell using a vesicle. B. the vesicle fuses with the cell membrane.C. golgi body-proteins modified here are released from the cell using exocytosis
32 Review Question 7. What is active transport? 8. How does a sodium-potassium pump work?9. What are the similarities and differences between endocytosis and exocytosis?10. What is the function of a receptor protein?
33 How do multicellular organism maintain homeostasis? Cell specialization- in order for cells to be effective, they must work together.Teamwork
34 Levels of Organization in multicellular organisms
35 Levels of Organization Cells- group of ORGANELLES working together to perform a particular function.Tissue- a group of cells working together to perform a particular function.Organ- a group of tissues working together to perform a particular function.Organ system- a group of organs working together to perform a particular function.Organism- all organ systems working together to maintain homeostasis
37 Answer: Membrane Receptor Proteins Receive Information 1. Cells release signal molecules that carry info (hormones).2. Receptor proteins-binds to specific receptor molecules3. They can speed up or slow down cell activities.